Testing of full scale ventilator cap types to determine their effect on natural ventilation

Conference · Thu Jan 01 04:00:00 EST 1981 · Proc. Annu. Meet. - Am. Sect. Int. Sol. Energy Soc.; (United States)

OSTI ID:5836967

Schubert, R P; Kennedy, B

Natural ventilation in building design is the result of air movement induced by differences in temperature and pressure. A building placed in the path of a moving air stream generates wind-caused pressure differentials that are indicative of the building's shape. These pressure differentials can be used to displace air and hence, induce ventilation. This study investigates what happens when given forms are added to the building to enhance natural ventilation. Preliminary research has looked at scale models of ventilator caps tested within a low velocity, open throat wind tunnel. Further work has been done to verify the relative performance factors that were generated by the small-scale tests. This verification procedure involved testing full-scale ventilator caps in a 6' x 6' x 24' test section of a closed loop tunnel. The shapes tested included air shields, delta wings, turbine ventilators, and exaggerated wing sections as well as the uncapped stack itself. Each of these geometries was placed on a full scale ventilator stack in the center of the air flow through the wind tunnel. The induced air movement through the stack at wind speeds ranging from 0 to 45 mph was monitored using a pitot tube. As with the tests of the smaller models, wind velocity, angle of attack, and yaw angle were plotted and recorded against induced air movement. Of particular interest in this study were the effects of wake and free column area on the flow rates through the stack.These effects were studied visually using tracer gas in the wind tunnel tests. The results of the full scale prototype tests indicated what relative contribution each cap type could make toward natural ventilation and summertime cooling.

• Research Organization: Virginia Polytechnic Inst. and State Univ., Blacksburg
• OSTI ID: 5836967
• Report Number(s): CONF-810509-(Vol.2)
• Conference Information: Journal Name: Proc. Annu. Meet. - Am. Sect. Int. Sol. Energy Soc.; (United States) Journal Volume: 4.2
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140901* -- Solar Thermal Utilization-- Space Heating & Cooling
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320100 -- Energy Conservation
Consumption
& Utilization-- Buildings
PERFORMANCE TESTING
STACKS
TESTING
TUNNELS
VENTILATION
VENTILATION SYSTEMS
WIND TUNNELS